The Virginia General Assembly will convene here on Wednesday for the primary purpose of correcting a $200-million miscalculation that it made jointly with Gov. Mills E. Godwin when the legislators last met. The solution may result in higher taxes.

On the last day of the 1976 legislative session 10 months ago, the Assembly approved a two-year budget that, according to current revenue forecasts, overestimated state tax receipts for 1976-78 by 6 per cent.

The cause of this collective error was an optimistic forecast of recovery from the national recession that was made by Godwin and his advisers and accepted without serious debate by the Assembly. The effect of it has been to plunge the governor and Assembly into an election-year debate over taxes and budget cuts.

A combination of economics ordered by Godwin and extension of federal revenue sharing - not counted on when the budget was adopted - has reduced the revenue gap to $120 million. The governor has said that to avoid disruptive cuts in services, the Assembly will have to close at least part of that gap with new or higher taxes.

In addition to the budget debate, a number of other recurring and often emotional issues are expected to reappear in the coming session. These include proposals for state government reorganization, revision of divorce laws, capital punishment and ratification of the proposed federal Equal Rights Amendment.

The annual debate over collective bargaining rights for state and local government employees has been diverted to the court's this year. An Arlington Circuit Court judge has ruled that Virginia employees have the right to bargain collectively. The ruling was appealed to the state Supreme Court at the direction of Godwin, who contends that the state law prohibits contracts with public employee unions. The Supreme Court could rule as early as next Friday.

Under the Virginia scheme of government, this Assembly session is supposed to be a 30-day meeting devoted primarily to general legislation. Because of the necessity to make a major budget revision, however, legislative leaders are uniformly predicting that the coming session will be extended to at least 45 days and perhaps to the constitutional limit of 60 days.

Godwin first revealed the magnitude of the projected revenue shortfall to legislators on Nov. 8 at a meeting with members of appropriations and tax-writing committees. He has said he will propose no specific taxes or budget cuts until the Assembly has a chance to develop a consensus on what should be done.

Both House and Senate majority leaders - Sen. Adelard L. Brault (D-Fairfax) and Del. James M. Thompson (D-Alexandria) - said in recent interviews that no such consensus has yet developed. Both predicted, however, that the Assembly will agree on a combination of tax increase and budget cuts.

"The only thing I can say for certain before the session is that we will not permit any reductions in state aid to localities for public education," Brault said. "We are not likely to provide any new tax revenues for localities, but we won't cut back aid approved in the budget last year."

Godwin has warned that if the Assembly leaves it to him to make up all of the revenue gap with further budget cuts, he will reduce state aid to cities and counties, probably by $80 million. A $20 million cut in aid to localities to close a revenue gap last year brought loud objections from city and county officials.

Those officials this year are lobbying vigrously not only for full delivery of the money already promised to them but also for new local tax revenues. They have asked for a 1 per cent increase in the statewide 4 per cent sales tax and a limited local income tax. They are not expected to get either.

A penny increase in the sales tax has so far been the most frequently discussed tax alternative, but if it is adopted the state is considered likely to keep all of the $140 million it would produce. Cities and counties, as Brault suggested, would get only a guarantee that already promised aid will be delivered.

Other than a sales tax increase, the most widely discussed revenue possibilities are an income tax increase for persons earning more than $12,000, an increase in the state's low 2.5-cent per pack cigarette tax and a tax on the first sale of newly mined coal.

Godwin proposed a 4 per cent coal tax last year and the Senate approved a 3 per cent levy. The measures was defeated in the House where delegates from the coal-producing counties in Southwest Virginia forged alliances with other regions to beat it.

Most Northern Virginia delegates voted against the coal tax in exchange for support for state aid to the Metrorail system. They ended up with no Metrorail aid, however, because Godwin vetoed a $10-million construction grant and Fairfax City vetoed implementation of a regional gasoline tax.

Sen. Omar L. Hirst (D-Fairfax), senior member of the Fairfax County delegation, said in an interview that an attempt to revive the gas tax is certain. "The authority for a 4 per cent tax is still on the books for another 18 months," he said. "There probably will be an effort either to make it permanent or to let individual cities and counties impose it without a regional agreement," as was required in last year's gas tax legislation.

Hirst said that the failure of Northern Virginia to make use of the taxing authority granted last year probably will hurt chances for reviving it this year.

The gasoline tax was intended to pay the region's Metrobus operating deficit for the two years ending in mid-1978. Any further state aid for the ever-rising rail construction costs also appears unlikely, Thompson said.

In order to win federal approval of completion of Interstate Rte. 66 inside the Capital Beltway, Godwin has agreed to use $75 million in interstate highway money to aid Metro construction. He has made no promise for future aid to Metro, however. He has often said that the project is too costly to be feasible and is considered certain not to reverse that long-standing view in the last 12 months of his four-year term.

Brault and Thompson agree that government reorganization is going to be the most controversial issue other than taxes and budget cuts. A fight is expected over proposals to regroup the agencies overseeing agriculture and commerce and to give the governor greater power to appoint and remove agency heads and members of boards and commissions.

Efforts to win ratification of the federal Equal Rights Amendment will again focus on the Senate, where it was rejected by the Privileges and Election Committee last year, 8 to 7. Hirst, the committee's chairman, said he will consider moving for discharge of his committee from consideration of the measure in order to get it before the Senate, but only after polling both the panel members and the full Senate on their wishes.

The seven female members of the 100-member House - there are no female senators - have prefiled a bill reviving proposed revisions in the divorce laws. They want to give divorce courts the power to divide property and to allocate ownership or use of the family home on the basis of need. The responsibility of each spouse for care of children of the marriage would be a major consideration in establishing need.

Capital punishment laws will be up for revision again because a U.S. Supreme Court ruling has made existing ones unenforceable in Virginia. There is overwhelming support for a death penalty in the Assembly, but the debate over how many crimes should be covered is usually intense.

As a prelude to the state wide elections later this year, the Assembly will choose a temporary successor to Attorney General Andrew P. Miller, who has said he will resign Jan. 17 to devote full time to his campaign for the Democratic nomination for governor. He is opposed bby former Lt. Gov. Henry E. Howell Jr.